Tuesday, July 28, 2015

Combining Balls Animation -- Epic Color Crash Step 4

OK it has been a couple of days since the last step was posted. I am splitting my time between a couple of web service applications, a new game, this tutorial, selling stuff on eBay, and sometime I should work on getting a job. Anyway it is time for the next step.

Preview: Here is what the game will be like at the end of this step:
video


Now that we have the images for the animations created we can start the game logic. The first thing I am going to add is the ability to swipe between two primary colored balls to produce a secondary colored ball.

I don't really need to do a swipe detection, all I really need to do is on a touchesBegan check and see what ball, if any, the user touched. Then on the touchesMoved check and see if the touch has moved to a different ball. Then if the balls are allowed to combine we can combine the balls.

The touchesBegan function in GameScene.swift currently looks like this:
    override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
        /* Called when a touch begins */
        
        for touch in (touches as! Set<UITouch>) {
        }

    }

First we want to get the location of the touch in the local coordinates. Inside the for loop add:
let location = touch.locationInNode(self)

Now we want to see if there are any balls at this location. self.nodesAtPoint(location) will give us a list of all of the scenes child nodes that are at the location. These nodes may or may not be a colored ball. So I will create an optional called startBall. Add startBall right after the declaration for newBallDelay in the Game scene class.
class GameScene: SKScene {
    var lastBallDropped: CFTimeInterval = 0
    var newBallDelay: CFTimeInterval = 1.5
    var startBall: ColoredBall?

We will then get the list of nodes at the touch location, assuming there is at least one node we will try and set the startBall to the touched node as a ColoredBall. If the node is not an object with the class of ColoredBall then startBall will be set to no value. However if it is a ColoredBall object then the optional will be set. When this happens we don't need to look at anymore nodes or anymore touches and we can just return. So after let location = touch.locationInNode(selfadd:

            let balls = self.nodesAtPoint(location)
            if balls.count >= 1 {
                for aBall in balls {
                    startBall = aBall as? ColoredBall;
                    if startBall != nil {
                        return
                    }
                }
            }

Now we want to get touchesMoved events and see if the user swipes into a different ball. We add the touchesMoved function and like the touchesBegan convert the touch location to our local coordinates, and check to see if there is a ColoredBall at that location. If there is a ColoredBall at that location than we make sure we have a starting ball, and the starting ball is not the same as the ball being touched. If that is the case than we can try and combine the balls.
 
    override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
        for touch in (touches as! Set<UITouch>) {
            let location = touch.locationInNode(self)
            let aBall:ColoredBall? = self.nodeAtPoint(location) as? ColoredBall
            if startBall != nil && aBall != nil && aBall != startBall {
                primaryContact(startBall!, spriteB: aBall!)
                startBall = nil
                return
            }
            
        }
    }

The way this is written the first touch has to be in a ball, however we could change it so that if the startBall is not set then we would set the startBall to the current ball being touched which would allow a swipes that pass through two balls but didn't start in a ball. I could change this in my current game, but the method above works well.

I have added a call to a new function primaryContact let's write that function. The function will take two colored balls and check to see if they are colors that can be combined, if so combine to make a new colored ball. This is a big nested set of if else code. Given that in sprite you can have switch statements with strings this could be rewritten with switch statements. However eventually I will convert this code to Objective-C and to C++ which would require it to be if else statements. Since either works just fine I will stick to the classic if else method.

We create a the function:
    func primaryContact(spriteA: ColoredBall, spriteB: ColoredBall) {

If the first ball is red then check and see if the second ball is yellow or blue, if so create an orange or purple ball.
        if spriteA.name == "red" {
            if spriteB.name == "yellow" {
                // make an orange ball
                ebcc_combineSprites(spriteA, spriteB: spriteB, color: "orange")
                orangeBalls.insert(spriteB)
            } else if spriteB.name == "blue" {
                // make a purple ball
                ebcc_combineSprites(spriteA, spriteB: spriteB, color: "purple")
                purpleBalls.insert(spriteB)
                
            }
OK, same thing if the first ball is yellow but test for red and blue to get orange and green. 
        } else if spriteA.name == "yellow" {
            if spriteB.name == "red" {
                // make an orange ball
                combineSprites(spriteA, spriteB:spriteB, color: "orange")
            } else if spriteB.name == "blue" {
                // make a green ball
                combineSprites(spriteA, spriteB: spriteB, color: "green")
            }

And finally if the first is blue then red to purple and yellow to green.
        } else if spriteA.name == "blue" {
            if spriteB.name == "red" {
                // make a purple ball
                combineSprites(spriteA, spriteB: spriteB, color: "purple")
                purpleBalls.insert(spriteB)
            } else if spriteB.name == "yellow" {
                // make a green ball
                combineSprites(spriteA, spriteB: spriteB, color: "green")
            }
        }
        
    }
But I still have not written the code to combine the sprites. Let's do that now. The combineSprites function will take two colored balls and string designating the new color. 
    func combineSprites(spriteA: ColoredBall, spriteB: ColoredBall, color: String) {
First I will move the second ball to be halfway between the two balls.
        spriteB.position.x = (spriteA.position.x + spriteB.position.x) / 2
        spriteB.position.y = (spriteA.position.y + spriteB.position.y) / 2
Then we will run a little animation that will turn the second ball into one with the new color.
        switch color {
        case "orange":
            spriteB.runAction(orangeAction!)
        case "green":
            spriteB.runAction(greenAction!)
        case "purple":
            spriteB.runAction(purpleAction!)
        default:
            spriteB.texture = SKTexture(imageNamed: color)
        }

Here I did use the switch statement instead of a bunch of if else statements. When we create the Objective-C and C++ code this will have to change. The switch statement in Swift requires a default case. This should never happen because we always send orange, green, or purple. However if for some strange reason we added some other color then we will just change the texture to an image with that color as the name. Again this never happens.

Now I want to remove the first ball from the scene. And since it will no longer have anything referencing it, it will be freed.
        spriteA.removeFromParent()

And finally I will change the name of the second sprite to the new color. This is critical so that we can test if it is touching other secondary colored balls and also so our touchesBegan and touchesMoved functions don't think it is a primary colored ball.
        spriteB.name = color
    }

OK they are combined, but I added the use of some actions that are not defined yet. Finally we get to use the animation images we created in the last step.

First I'll add optionals for each color action, and then a sound action to play when the balls are combined. I found a public domain sound that I downloaded. I'll let you go find your own. On the sound action I use waitForCompletion to tell it to start the drip sound and then continue with other actions.
    var orangeAction: SKAction?
    var greenAction: SKAction?
    var purpleAction: SKAction?
    var dripSound = SKAction.playSoundFileNamed("drip.wav", waitForCompletion: false)

We need to actually assemble the actions. I'll do that in the scene's didMoveToView function right after the self.physicsBody = SKPhysicsBody(edgeLoopFromRect: self.frame)
First I'll check to see if the action already was created in a previous didMoveToView call
        if orangeAction == nil {

Then I'll get an atlas with the animation images. The problem is we are not guaranteed what order they will be in. So I sort them and then I can create an animation with 0.075 seconds between images for just a little less than half a second total. Then I can create an sequence that plays the sound and then runs the image animation.
            let orangeAtlas = SKTextureAtlas(named: "orange")
            let orangeTextures = sorted(orangeAtlas.textureNames as! [String]).map { orangeAtlas.textureNamed($0) }
            let orangeAnimation = SKAction.animateWithTextures(orangeTextures, timePerFrame: 0.075)
            orangeAction = SKAction.sequence([dripSound,orangeAnimation])
        }
Repeat for green and purple
        if greenAction == nil {
            let greenAtlas = SKTextureAtlas(named: "green")
            let greenTextures = sorted(greenAtlas.textureNames as! [String]).map { greenAtlas.textureNamed($0) }
            let greenAnimation = SKAction.animateWithTextures(greenTextures, timePerFrame: 0.075)
            greenAction = SKAction.sequence([dripSound,greenAnimation])
        }
        if purpleAction == nil {
            let purpleAtlas = SKTextureAtlas(named: "purple")
            let purpleTextures = sorted(purpleAtlas.textureNames as! [String]).map { purpleAtlas.textureNamed($0) }
            let purpleAnimation = SKAction.animateWithTextures(purpleTextures, timePerFrame: 0.075)
            purpleAction = SKAction.sequence([dripSound,purpleAnimation])
        }

Now we need to add the images and sound to our project. Previously I created a group called images, but I am going to be putting sounds in here too, so I am going to rename it assets, a much better name.

Then File->Add Files to "EpicColorCrash"... and select the atlas directories we created in the last step.
Make sure Copy items if needed is selected and Create groups is selected. And click Add. Then download or create a sound for the drip.wav and add it to the project.


Build and run. Now you should be able to swipe between balls, get a cool little animation and a sound.
Here is the GameScene.swift file at the end of this step:
//
//  GameScene.swift
//  Epic Color Crash
//
//  Created by Daniel Burton on 7/25/15.
//  Copyright (c) 2015 Daniel Burton. All rights reserved.
//

import SpriteKit

class ColoredBall: SKSpriteNode {
}

class GameScene: SKScene {
    var lastBallDropped: CFTimeInterval = 0
    var newBallDelay: CFTimeInterval = 1.5
    var startBall: ColoredBall?
    var orangeAction: SKAction?
    var greenAction: SKAction?
    var purpleAction: SKAction?
    var dripSound = SKAction.playSoundFileNamed("drip.wav", waitForCompletion: false)

    func addColorBall(location: CGPoint, withColor color:String) {
        let sprite = ColoredBall(imageNamed: color)
        
        sprite.position = location
        sprite.name = color
        let body = SKPhysicsBody(circleOfRadius: 25)
        sprite.physicsBody = body
        body.allowsRotation = false
        body.friction = 0.0
        self.addChild(sprite)
    }
    
    func combineSprites(spriteA: ColoredBall, spriteB: ColoredBall, color: String) {
        spriteB.position.x = (spriteA.position.x + spriteB.position.x) / 2
        spriteB.position.y = (spriteA.position.y + spriteB.position.y) / 2
        switch color {
        case "orange":
            spriteB.runAction(orangeAction!)
        case "green":
            spriteB.runAction(greenAction!)
        case "purple":
            spriteB.runAction(purpleAction!)
        default:
            spriteB.texture = SKTexture(imageNamed: color)
        }
        spriteA.removeFromParent()
        spriteB.name = color
    }

    func primaryContact(spriteA: ColoredBall, spriteB: ColoredBall) {
        if spriteA.name == "red" {
            if spriteB.name == "yellow" {
                // make an orange ball
                combineSprites(spriteA, spriteB: spriteB, color: "orange")
            } else if spriteB.name == "blue" {
                // make a purple ball
                combineSprites(spriteA, spriteB: spriteB, color: "purple")
                
            }
        } else if spriteA.name == "yellow" {
            if spriteB.name == "red" {
                // make an orange ball
                combineSprites(spriteA, spriteB:spriteB, color: "orange")
            } else if spriteB.name == "blue" {
                // make a green ball
                combineSprites(spriteA, spriteB: spriteB, color: "green")
            }
        } else if spriteA.name == "blue" {
            if spriteB.name == "red" {
                // make a purple ball
                combineSprites(spriteA, spriteB: spriteB, color: "purple")
            } else if spriteB.name == "yellow" {
                // make a green ball
                combineSprites(spriteA, spriteB: spriteB, color: "green")
            }
        }
        
    }
    
    override func didMoveToView(view: SKView) {
        
        /* Setup your scene here */
        self.scaleMode = .AspectFit

        self.physicsBody = SKPhysicsBody(edgeLoopFromRect: self.frame)
        if orangeAction == nil {
            let orangeAtlas = SKTextureAtlas(named: "orange")
            let orangeTextures = sorted(orangeAtlas.textureNames as! [String]).map { orangeAtlas.textureNamed($0) }
            let orangeAnimation = SKAction.animateWithTextures(orangeTextures, timePerFrame: 0.075)
            orangeAction = SKAction.sequence([dripSound,orangeAnimation])
        }
        if greenAction == nil {
            let greenAtlas = SKTextureAtlas(named: "green")
            let greenTextures = sorted(greenAtlas.textureNames as! [String]).map { greenAtlas.textureNamed($0) }
            let greenAnimation = SKAction.animateWithTextures(greenTextures, timePerFrame: 0.075)
            greenAction = SKAction.sequence([dripSound,greenAnimation])
        }
        if purpleAction == nil {
            let purpleAtlas = SKTextureAtlas(named: "purple")
            let purpleTextures = sorted(purpleAtlas.textureNames as! [String]).map { purpleAtlas.textureNamed($0) }
            let purpleAnimation = SKAction.animateWithTextures(purpleTextures, timePerFrame: 0.075)
            purpleAction = SKAction.sequence([dripSound,purpleAnimation])
        }

    }
    
    override func touchesBegan(touches: Set<NSObject>, withEvent event: UIEvent) {
        /* Called when a touch begins */
        
        for touch in (touches as! Set<UITouch>) {
            let location = touch.locationInNode(self)
            let balls = self.nodesAtPoint(location)
            if balls.count >= 1 {
                for aBall in balls {
                    startBall = aBall as? ColoredBall;
                    if startBall != nil {
                        return
                    }
                }
            }
        }
    }
    override func touchesMoved(touches: Set<NSObject>, withEvent event: UIEvent) {
        for touch in (touches as! Set<UITouch>) {
            let location = touch.locationInNode(self)
            let aBall:ColoredBall? = self.nodeAtPoint(location) as? ColoredBall
            if startBall != nil && aBall != nil && aBall != startBall {
                primaryContact(startBall!, spriteB: aBall!)
                startBall = nil
                return
            }
            
        }
    }

    override func update(currentTime: CFTimeInterval) {

        // if the time has come to drop a new ball
        if currentTime > (lastBallDropped + newBallDelay) {
                lastBallDropped = currentTime
                let colors = ["red", "yellow", "blue"]
                var xpos = Int(arc4random_uniform(UInt32(self.size.width-100) ))+50
                let ypos = self.size.height - 120
                let location = CGPoint(x: xpos, y: Int(ypos))
                var colorIndex = arc4random_uniform(3)
                addColorBall(location, withColor: colors[Int(colorIndex)])
        }

    }
    

}

Sunday, July 26, 2015

Creating Swirling Ball Animations -- Color Crash Step 3


Now that we have balls dropping into the game it is time to start adding in some game logic. Eventually the screen will be so full of balls that there isn't room for anymore, but I'll leave the game over logic for later, first I want to start combining balls. I want to make it so that swiping between two primary colored balls produces a secondary colored ball. When this happens I could just remove one of the balls and then change the other ball into the new color, but it would be nice if there was a animation that happens when the balls are combined. So I am going to need some animation images.

My daughter went to BYU and their school color is blue, she just married a guy who is going to the rival school the University of Utah whose color is red, so their wedding color was purple, and that is the first animation I'll do, turning a red and a blue into a purple.

In Gimp I will open up my purple.xcf file that we created in step 1 and zoom into 400%.
 
Now I am going to open the red.xcf and blue.xcf files as layers. In the menu File->Open as Layer and select both the red and blue files. I can see in the Layers - Brushes window that I have a bunch of transparent layers with nothing in them.
I don't need the empty layers. I'll select the empty layers and click on the little trash can to delete them. I now have a red layer a blue layer and a purple layer. Now I create a mask for the red layer by selecting the red layer and then in the menu Layer->Mask->Add Layer Mask... Select the White (full opacity) option and click on Add.
Now click on the new white mask layer next to the red layer to select it.
Now I want to make make a transparent spiral in the mask which will reveal some of the blue layer below. So in the Toolbox window I will select the pencil tool and set the brush size to be 5 and make sure the color is black.
I will now draw a spiral on the red ball which will reveal the blue ball below, and in the Layer - Brushes window you will see the spiral show up on the mask.
This will be the first image in my animation, so I will save it as purple001.xcf, then create a new directory called purple.atlas and and export it as purple001.png putting the png file in the atlas directory. 
OK, now I'll select the blue layer in the Layer - Brushes window and in the menu Layer->Mask->Add Layer Mask... select a White (full opacity) and Add. Then select the new mask layer.
Once again I will draw a spiral on the mask but last time I did a counter clockwise spiral and this time I will do a clockwise spiral to get a mixing effect. 
I want things to look like they are swirling so the red mask I am going to rotate counter clockwise. First I select the red mask in the Layers - Brushes window and then in the menu Select->All then click on the rotate tool in the Toolbox and click and drag counter clockwise a few degrees.

Then I'll click on the little anchorin the Layers - Brushes window to finish the rotation. And then save as purple002.xcf and export as purple002.png

I now select the red mask, rotate it a few degrees counter clockwise again then draw a new spiral in the mask.
Then I'll select the blue mask rotate it a few degrees clockwise and draw a new clockwise spiral using the pencil. We are now getting a nice mix of red blue and purple. I'll save this as purple003.xcf and export as purple003.png.

Then repeat the rotating the masks and drawing the spirals 2 more times each time saving then next image in the animation, purple004 and purple005.

Then copy the purple.png file from the images.atlas directory to the purple.atlas directory and rename it to purple006.png. I now have a 6 image animation that for combining a red and blue ball to create a purple ball.

I can now repeat this process with green blue and yellow, and orange red and yellow to create animations for green and orange. 
After creating the orange an green animations I can now go back to Xcode and select my images group and the menu File->Add Files to "Epic Color Crash" 
Now we are ready to do some more programming which will be the next step.

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